What we learned mapping 40 chilli fields on a phone with no signal

Mapping a field is a five-minute job. Doing it forty times, in one week, on borrowed phones, in a place where the network drops behind the first hill — that is a product requirement.

We went in assuming the hard part would be accuracy. It was not. GPS on an ordinary phone is good enough to draw a boundary a farmer recognises as theirs. The hard part was everything around the measurement: whose field it is, what was planted last season, whether the person walking the edge is the owner or the owner's son, and what happens when the app cannot reach the server for three hours.

Offline is the default, not the fallback

Every screen in FarmTrace has to work with no connection and reconcile later. That single decision changed how we store a field: the boundary is written locally with a device-side identity, and the server resolves duplicates when it eventually hears from the phone. Two officers mapping the same field from opposite corners is a normal Tuesday, not an error state.

A record nobody can correct in the field is a record nobody trusts.

The boundary is a key, not a picture

Once a field exists as a shape, everything else can hang off it — satellite passes, weather, the crop cycle, the spray log, the consignment that left it. That is the whole reason we ask someone to walk the edge in the first place. Without it, a weather alert can only say "rain is coming". With it, the alert can name the field, the crop and the day.

Forty fields later, the mapping flow has three screens instead of seven, and the officer can finish a farm in under four minutes. That is the version that survived contact with a real week.